GO:0004758 serine C-palmitoyltransferase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0004758 defines the enzymatic activity that catalyzes the committed step of de novo sphingolipid biosynthesis: the condensation of L-serine with palmitoyl-CoA to form 3-dehydrosphinganine.
• The reaction requires pyridoxal 5'-phosphate (PLP) as a cofactor and releases CO2 and CoA.
• The enzyme is a heterodimer typically composed of SPTLC1 or SPTLC2 with SPTLC3 or SPTLC2, and its subunit composition influences substrate specificity and tissue distribution.
• Dysregulation of serine C-palmitoyltransferase activity is linked to metabolic diseases including MASH, ischemic cardiomyopathy, and hepatic gluconeogenesis disorders.
• Inhibitors such as L-cycloserine and myriocin target this activity, making it a therapeutic target for sphingolipid-driven pathologies.
• CRISPR-based models (knockout, point mutation, knock-in, overexpression) are essential to dissect the roles of SPTLC subunits in health and disease.
Description
Serine C-palmitoyltransferase (SPT) activity, encoded by GO:0004758, is the rate-limiting enzymatic step in the de novo synthesis of sphingolipids, a class of bioactive lipids critical for membrane structure and signaling. This activity catalyzes the condensation of L-serine with palmitoyl-CoA to produce 3-dehydrosphinganine, carbon dioxide, and coenzyme A. Because sphingolipids are involved in diverse cellular processes such as apoptosis, differentiation, and inflammation, SPT activity is a focal point for understanding metabolic regulation and disease. Research over the past decades has revealed that SPT is not a single protein but a heterodimeric complex with multiple subunit isoforms, including SPTLC1, SPTLC2, and SPTLC3, which confer distinct catalytic properties and tissue-specific functions. The dysregulation of SPT activity has been implicated in conditions ranging from hepatic steatosis to cardiomyopathy, underscoring its clinical relevance. This article provides a comprehensive overview of GO:0004758, covering its definition, mechanism, key genes, disease associations, and modern research methodologies, including CRISPR-based approaches to study its function.
serine C-palmitoyltransferase activity At A Glance
| GO ID | GO:0004758 |
|---|---|
| GO term | serine C-palmitoyltransferase activity |
| Ontology | molecular_function |
| Synonym | 3-oxosphinganine synthetase activity, serine palmitoyltransferase, SPT |
| Definition | Catalysis of the reaction: L-serine + H+ + palmitoyl-CoA = 3-dehydrosphinganine + CO2 + CoA. |
| Major function | Rate-limiting step in de novo sphingolipid biosynthesis |
| Cofactor | Pyridoxal 5'-phosphate (PLP) |
| Substrates | L-serine and palmitoyl-CoA |
| Products | 3-dehydrosphinganine, CO2, CoA |
What Is GO:0004758?
GO:0004758, serine C-palmitoyltransferase activity, is a molecular function defined by the catalysis of the reaction: L-serine + H+ + palmitoyl-CoA = 3-dehydrosphinganine + CO2 + CoA. In simpler terms, it is the enzyme activity that joins the amino acid serine with a fatty acid molecule (palmitoyl-CoA) to create the first sphingolipid backbone, a critical building block for all sphingolipids.
Why Is serine C-palmitoyltransferase activity Important in Cell Biology?
Serine C-palmitoyltransferase activity is the gateway to all sphingolipid biosynthesis, and its regulation directly impacts cellular membrane composition, lipid signaling, and energy metabolism. Alterations in this activity have been causally linked to metabolic disorders such as MASH, ischemic cardiomyopathy, and impaired gluconeogenesis, making it a prime target for therapeutic intervention. Understanding its precise molecular mechanism and regulation is therefore essential for developing treatments for these conditions.
• Controls the rate-limiting step of de novo sphingolipid synthesis, affecting membrane fluidity and lipid raft formation.
• Dysregulation contributes to metabolic dysfunction-associated steatohepatitis (MASH).
• SPTLC3 subunit is essential for complex I activity and contributes to ischemic cardiomyopathy.
• Regulates plasma membrane sphingolipid composition to facilitate hepatic gluconeogenesis.
• Inhibitors of SPT activity, such as L-cycloserine, reduce sphingolipid levels and are used experimentally.
• Nicotinamide increases ceramide biosynthesis via SPT activity, improving epidermal barrier function.
• Very long-chain fatty acids can drive 1-deoxysphingolipid toxicity through SPT-dependent pathways.
• SPT subunit 3 is linked to metabolic diseases, highlighting its potential as a biomarker or drug target.
Mechanism, Genes and Research Methods
Substrate Binding and Condensation
In simple terms: The enzyme grabs serine and palmitoyl-CoA and joins them together.
The catalytic mechanism begins with the binding of L-serine and palmitoyl-CoA to the active site of the SPT complex. The enzyme utilizes pyridoxal 5'-phosphate (PLP) as a cofactor to facilitate the condensation reaction, forming a Schiff base with the amino group of serine. This step is the committed and rate-limiting step in sphingolipid biosynthesis.
Formation of 3-Dehydrosphinganine
In simple terms: The joined molecule loses carbon dioxide and CoA to become the first sphingolipid backbone.
Following condensation, the intermediate undergoes decarboxylation, releasing CO2 and CoA, resulting in the formation of 3-dehydrosphinganine (also known as 3-ketodihydrosphingosine). This product is then rapidly reduced to dihydrosphingosine (sphinganine) by 3-ketodihydrosphingosine reductase in subsequent steps of the pathway.
Subunit Composition and Isoforms
In simple terms: The enzyme is made of different protein subunits that can vary by tissue.
SPT is a heterodimer typically composed of SPTLC1 paired with either SPTLC2 or SPTLC3. The SPTLC3 subunit is essential for complex I activity and contributes to ischemic cardiomyopathy. SPTLC3 also regulates plasma membrane sphingolipid composition to facilitate hepatic gluconeogenesis. The differential expression of these subunits influences substrate specificity and tissue-specific functions.
Regulation by Metabolic and Hormonal Signals
In simple terms: The enzyme's activity can be turned up or down by cellular signals.
SPT activity is regulated at multiple levels, including transcriptional control of subunit genes and post-translational modifications. For example, nicotinamide increases ceramide biosynthesis via SPT activity in epidermal cells. Additionally, very long-chain fatty acids can drive 1-deoxysphingolipid toxicity through SPT-dependent pathways, indicating that substrate availability and lipid environment modulate activity.
Inhibitors and Pharmacological Tools
In simple terms: Certain chemicals can block the enzyme, which is useful for research and therapy.
L-cycloserine is a known inhibitor of serine palmitoyltransferase activity, as demonstrated in rabbit aorta. Myriocin is another potent inhibitor commonly used in research. These inhibitors are valuable for dissecting the biological roles of sphingolipids and for developing therapeutics targeting SPT in diseases like MASH.
Key Genes Involved in GO:0004758 serine C-palmitoyltransferase activity
The following genes encode proteins that constitute or directly regulate serine C-palmitoyltransferase activity.
| Gene | Major Role | Research Relevance |
|---|---|---|
| SPTLC1 | Core subunit of SPT heterodimer | Mutations linked to hereditary sensory neuropathy; essential for activity |
| SPTLC2 | Catalytic subunit, alternative to SPTLC3 | Determines substrate specificity; knockout models show embryonic lethality |
| SPTLC3 | Regulatory subunit, tissue-specific | Essential for complex I activity; contributes to ischemic cardiomyopathy |
| SPTLC3 | Regulates plasma membrane sphingolipid composition | Facilitates hepatic gluconeogenesis; potential target for diabetes |
| SPTSSA | Small subunit, stabilizes SPT complex | Modulates SPT activity; mutations affect sphingolipid levels |
| SPTSSB | Small subunit, alternative to SPTSSA | Tissue-specific regulation of SPT activity |
| ORMDL1 | Negative regulator of SPT | Inhibits SPT activity; involved in sphingolipid homeostasis |
| ORMDL2 | Negative regulator of SPT | Modulates SPT in response to sphingolipid levels |
| ORMDL3 | Negative regulator of SPT | Associated with asthma and inflammation |
| KDSR | 3-ketodihydrosphingosine reductase | Converts 3-dehydrosphinganine to sphinganine; downstream of SPT |
| CERS1 | Ceramide synthase | Uses sphinganine to produce ceramides; downstream of SPT |
| CERS2 | Ceramide synthase | Involved in very long-chain ceramide synthesis |
| CERS5 | Ceramide synthase | Contributes to MASH pathogenesis |
| CERS6 | Ceramide synthase | Linked to hepatic de novo ceramide synthesis |
| DEGS1 | Dihydroceramide desaturase | Introduces double bond to form ceramides |
| SGMS1 | Sphingomyelin synthase | Produces sphingomyelin from ceramide |
| UGCG | Glucosylceramide synthase | Produces glucosylceramide; branch point |
How Is serine C-palmitoyltransferase activity Regulated?
Serine C-palmitoyltransferase activity is regulated by multiple mechanisms. The ORMDL proteins (ORMDL1, ORMDL2, ORMDL3) act as negative regulators of SPT, responding to cellular sphingolipid levels to maintain homeostasis. Transcriptional regulation of SPTLC subunits occurs in response to metabolic demands; for instance, SPTLC3 expression is modulated in hepatic gluconeogenesis. Post-translational modifications and availability of substrates (serine and palmitoyl-CoA) also influence activity. Additionally, nicotinamide has been shown to increase ceramide biosynthesis via SPT activity in epidermal cells, suggesting a role for NAD+ metabolism in regulation.
serine C-palmitoyltransferase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| SPTLC3 | Ischemic cardiomyopathy | Cardiomyocyte-specific knockout |
| SPTLC3 | Hepatic gluconeogenesis | Liver-specific knockout or overexpression |
| SPTLC1/2 | Hereditary sensory neuropathy | Patient-derived iPSCs with point mutations |
| ORMDL3 | Asthma and inflammation | Knockout mice or airway epithelial cells |
| CERS5/6 | MASH | Liver-specific knockout or pharmacological inhibition |
Metabolic Dysfunction-Associated Steatohepatitis (MASH)
Targeted inhibition of hepatic de novo ceramide synthesis, which is downstream of SPT activity, ameliorates MASH in preclinical models. This suggests that excessive SPT activity contributes to hepatic lipid accumulation and inflammation, making it a potential therapeutic target.
Ischemic Cardiomyopathy
SPTLC3, a subunit of SPT, is essential for complex I activity and contributes to ischemic cardiomyopathy. Loss of SPTLC3 impairs mitochondrial function and exacerbates cardiac injury, highlighting the role of SPT activity in cardiac metabolism.
Hepatic Gluconeogenesis and Diabetes
SPTLC3 regulates plasma membrane sphingolipid composition to facilitate hepatic gluconeogenesis. Dysregulation of this process may contribute to hyperglycemia in type 2 diabetes, suggesting that SPT activity is a metabolic regulator.
1-Deoxysphingolipid Toxicity
Very long-chain fatty acids drive 1-deoxysphingolipid toxicity through SPT-dependent pathways. These atypical sphingolipids are implicated in peripheral neuropathy and other pathologies, linking SPT activity to neurotoxicity.
From serine C-palmitoyltransferase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does SPTLC3 loss affect mitochondrial complex I? | SPTLC3 knockout in cardiomyocytes |
| How does SPTLC3 regulate gluconeogenesis? | Liver-specific SPTLC3 knockout mice |
| What is the role of SPTLC1 in neuropathy? | Knock-in mice with patient mutations |
| Can SPT inhibition ameliorate MASH? | Pharmacological inhibition or liver-specific knockout |
| How do ORMDL proteins regulate SPT? | ORMDL knockout or overexpression cell lines |
| What is the impact of SPT on epidermal barrier? | Keratinocyte-specific knockout or nicotinamide treatment |
How to Study the serine C-palmitoyltransferase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Radioenzymatic assay | SPT enzymatic activity | Kinetic studies and inhibitor screening |
| LC-MS lipidomics | Sphingolipid species | Disease biomarker discovery |
| CRISPR knockout | Gene function | Target validation in disease models |
| RNA-seq | Transcriptional changes | Pathway analysis and regulatory networks |
| Proteomics | Protein expression and modifications | Subunit composition and post-translational regulation |
| Immunofluorescence | Subcellular localization | SPT complex assembly and trafficking |
| CRISPR library screening | Genome-wide fitness | Identify synthetic lethal partners |
| Bioinformatics pathway analysis | Enrichment of sphingolipid pathways | Integrative omics interpretation |
Enzymatic Activity Assays
Serine C-palmitoyltransferase activity can be measured using radiolabeled substrates (e.g., [3H]serine) and quantifying the formation of 3-dehydrosphinganine or downstream products. This method is fundamental for characterizing SPT kinetics and inhibition.
Lipidomics and Mass Spectrometry
Mass spectrometry-based lipidomics allows comprehensive profiling of sphingolipids, including ceramides and sphingomyelins, to assess SPT activity in cells and tissues. This approach is essential for linking SPT function to disease phenotypes.
CRISPR-Cas9 Genome Editing
CRISPR-Cas9 is used to generate knockout, point mutation, knock-in, and overexpression models of SPT subunit genes to dissect their specific roles. These models enable causal inference in metabolic and cardiovascular diseases.
Transcriptomics and Proteomics
RNA-seq and proteomics can reveal changes in SPT subunit expression and downstream sphingolipid pathway genes under various conditions. This helps identify regulatory networks and biomarkers.
How CRISPR Can Be Used to Study GO:0004758 serine C-palmitoyltransferase activity
Knockout
CRISPR knockout of SPTLC subunits (e.g., SPTLC3) in cell lines or animal models abolishes SPT activity, leading to sphingolipid depletion and revealing essential functions in mitochondrial complex I activity and cardiomyopathy. Liver-specific knockout of SPTLC3 impairs gluconeogenesis, demonstrating its metabolic role.
Point Mutation
Point mutations in SPTLC1 or SPTLC2 identified in hereditary sensory neuropathy can be introduced via CRISPR to model the disease and study how specific amino acid changes alter enzyme activity and substrate specificity.
Knock-in
Knock-in of tagged SPTLC1 (e.g., FLAG or GFP) allows for affinity purification and interactome analysis of the SPT complex, facilitating the identification of novel regulators and subunit composition.
Overexpression
Overexpression of SPTLC3 or SPTLC2 via CRISPR activation or lentiviral delivery increases SPT activity, enabling studies of lipid accumulation, gluconeogenesis, and ceramide-induced toxicity.
How EDITGENE Supports serine C-palmitoyltransferase activity Research
Researchers studying serine C-palmitoyltransferase activity-related genes often need to determine whether a candidate gene is causally involved in sphingolipid metabolism, metabolic disease, or cardiomyopathy. EDITGENE provides a comprehensive suite of CRISPR services to accelerate this discovery process.
Contact EDITGENE today to design your custom CRISPR model for serine C-palmitoyltransferase activity research.
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| SPTLC1 Knockout HEK293 Cell Line | EDJ-KQ1728 | Human | 10558 | Details Get a Quote |
| SPTLC2 Knockout HEK293 Cell Line | EDJ-KQ1729 | Human | 9517 | Details Get a Quote |
| SPTLC3 Knockout HEK293 Cell Line | EDJ-KQ1731 | Human | 55304 | Details Get a Quote |
| SPTSSB Knockout HEK293 Cell Line | EDJ-KQ15506 | Human | 165679 | Details Get a Quote |
| SPTLC2 Knockout HCT 116 Cell Line | EDJ-KQ20223 | Human | 9517 | Details Get a Quote |
| SPTLC1 Knockout A-549 Cell Line | EDJ-KQ21570 | Human | 10558 | Details Get a Quote |
| SPTLC1 Knockout HCT 116 Cell Line | EDJ-KQ21571 | Human | 10558 | Details Get a Quote |
| SPTLC1 Knockout HeLa Cell Line | EDJ-KQ21572 | Human | 10558 | Details Get a Quote |
| SPTLC2 Knockout A-549 Cell Line | EDJ-KQ21573 | Human | 9517 | Details Get a Quote |
| SPTLC2 Knockout HeLa Cell Line | EDJ-KQ21574 | Human | 9517 | Details Get a Quote |
| SPTLC3 Knockout HeLa Cell Line | EDJ-KQ21575 | Human | 55304 | Details Get a Quote |
| SPTSSB Knockout HCT 116 Cell Line | EDJ-KQ45073 | Human | 165679 | Details Get a Quote |
| SPTSSB Knockout HeLa Cell Line | EDJ-KQ58891 | Human | 165679 | Details Get a Quote |
| SPTLC3 Knockout A-549 Cell Line | EDJ-KQ65072 | Human | 55304 | Details Get a Quote |
| SPTSSB Knockout A-549 Cell Line | EDJ-KQ67380 | Human | 165679 | Details Get a Quote |
Displaying Records 1 To 15 Of 16 Records
Frequently Asked Questions About serine C-palmitoyltransferase activity
What is serine C-palmitoyltransferase activity?
It is the enzymatic activity (GO:0004758) that catalyzes the first committed step of sphingolipid synthesis: the condensation of L-serine with palmitoyl-CoA to form 3-dehydrosphinganine, CO2, and CoA.
What genes are involved in serine C-palmitoyltransferase activity?
The main genes are SPTLC1, SPTLC2, and SPTLC3, which encode subunits of the SPT complex, along with regulatory proteins like ORMDL1-3 and small subunits SPTSSA/B.
How is serine C-palmitoyltransferase activity regulated?
It is regulated by ORMDL proteins, transcriptional control of subunit genes, substrate availability, and post-translational modifications.
What diseases are associated with serine C-palmitoyltransferase activity?
Dysregulation is linked to MASH, ischemic cardiomyopathy, hepatic gluconeogenesis disorders, and hereditary sensory neuropathy.
What is the role of SPTLC3 in disease?
SPTLC3 is essential for mitochondrial complex I activity and contributes to ischemic cardiomyopathy, and it regulates hepatic gluconeogenesis.
How can I measure serine C-palmitoyltransferase activity?
Radioenzymatic assays using labeled serine or mass spectrometry-based lipidomics are common methods.
What are inhibitors of serine C-palmitoyltransferase?
L-cycloserine and myriocin are known inhibitors used in research and therapeutic studies.
Can CRISPR be used to study serine C-palmitoyltransferase activity?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models are powerful tools to dissect SPT subunit functions.
What is the connection between SPT and ceramide synthesis?
SPT produces 3-dehydrosphinganine, which is reduced to sphinganine and then used by ceramide synthases to produce ceramides.
Why is serine C-palmitoyltransferase important for skin?
Nicotinamide increases ceramide biosynthesis via SPT activity, improving epidermal permeability barrier function.
Conclusion
Serine C-palmitoyltransferase activity (GO:0004758) is a fundamental enzymatic function that governs the entry into sphingolipid biosynthesis. Its regulation is critical for metabolic homeostasis, and its dysregulation is implicated in a growing list of human diseases, including MASH, cardiomyopathy, and neuropathy. Continued research using advanced CRISPR models and lipidomics will further elucidate its mechanistic roles and therapeutic potential.
References
- 1. Yu X et al.. 2025. Targeted inhibition of hepatic de novo ceramide synthesis ameliorates MASH.. Sci Adv 11(39):eadx2681 PMID: 41004573
- 2. Kovilakath A et al.. 2024. SPTLC3 Is Essential for Complex I Activity and Contributes to Ischemic Cardiomyopathy.. Circulation 150(8):622-641 PMID: 38660786
- 3. Montefusco D et al.. 2024. SPTLC3 regulates plasma membrane sphingolipid composition to facilitate hepatic gluconeogenesis.. Cell Rep 43(12):115054 PMID: 39661520
- 4. Lone MA et al.. 2022. Serine Palmitoyltransferase Subunit 3 and Metabolic Diseases.. Adv Exp Med Biol 1372:47-56 PMID: 35503173
- 5. Merrill AH Jr. 1983. Characterization of serine palmitoyltransferase activity in Chinese hamster ovary cells.. Biochim Biophys Acta 754(3):284-91 PMID: 6652105
- 6. Majcher A et al.. 2025. Very long-chain fatty acids drive 1-deoxySphingolipid toxicity.. Nat Commun 16(1):11650 PMID: 41298489
- 7. Williams RD et al.. 1987. Inhibition of serine palmitoyltransferase activity in rabbit aorta by L-cycloserine.. J Lipid Res 28(12):1478-81 PMID: 3430071
- 8. Tanno O et al.. 2000. Nicotinamide increases biosynthesis of ceramides as well as other stratum corneum lipids to improve the epidermal permeability barrier.. Br J Dermatol 143(3):524-31 PMID: 10971324
